DUNDAS, Sir DAVID (1735–1820), general, was the third son of Robert Dundas, a merchant of Edinburgh, by his wife Margaret, daughter of Thomas Watson of Muirhouse. He was educated at the Royal Academy at Woolwich, and assisted in the great survey of Scotland under his maternal uncle, General David Watson, and under General Roy from 1752 to 1755. He was appointed a lieutenant fireworker in the royal artillery in 1754, a practitioner engineer in 1755, and a lieutenant in the 56th regiment in 1756, in which year he received the post of assistant quartermaster-general to General Watson. He threw up his staff appointment in 1758 to join his regiment when ordered on foreign service, and was present at the second Duke of Marlborough's attack on St. Malo, at General Bligh's capture of Cherbourg, and at the fight at St. Cas. At the close of the same year he joined the army under the command of Prince Ferdinand of Brunswick in the threefold capacity of assistant quartermaster-general, engineer, and lieutenant of infantry, and left Germany on the conclusion of the campaign to join the 15th light dragoons, into which he had just been promoted captain. Colonel Eliott, afterwards Lord Heathfield, who commanded that regiment, took a fancy to Dundas, who acted as his aide-de-camp in the campaigns of 1760 and 1761 in Germany, when he was present at the battles of Corbach, Warburg, and Clostercampen, the siege of Wesel, and the battle of Fellinghausen, and also in the expedition to Cuba in 1762, when Eliott served as second in command to Lord Albemarle at the capture of Havana. At the end of the seven years' war Dundas commenced that study of his profession which eventually caused him to be considered the most profound tactician in England. He was present every year at the manœuvres of the French, Prussian, or Austrian armies, and was able to get a thorough insight into the military reforms of Frederick the Great, which had revolutionised the armies of Europe. In 1770 he was promoted major, and when the war of American independence broke out in 1774 he was anxious to go on active service. On further consideration he thought it would be better for him rather to work out his new system of tactics, and he therefore purchased in 1775 the lieutenant-colonelcy of the 12th light dragoons instead. He was appointed quartermaster-general in Ireland in 1778, promoted colonel in 1781, and made lieutenant-colonel of the 2nd Irish horse in 1782, when he again had leisure to study the military systems of the continent. He attended the Prussian autumn manœuvres in Pomerania, Silesia, and Magdeburg in 1785, 1786, and 1787, and in 1788 he brought out the results of his long study in his great work, 'The Principles of Military Movements, chiefly applicable to Infantry.' The publication of this book made his reputation, and for the next ten years Dundas was constantly employed. In 1789 he was appointed adjutant-general in Ireland, on 28 April 1790 he was promoted major-general, and on 2 April 1791 made colonel of the 22nd regiment. In June 1792 the 'Rules and Regulations for the Formation, Field Exercises, and Movements of His Majesty's Forces,' which he had drawn up by the direction of the authorities at the Horse Guards, were issued as the official orders for the army, and were speedily followed by the 'Rules and Regulations for the Cavalry,' for which Dundas was largely indebted to the experience of Sir James Stewart Denham [q. v.] Under these rules and regulations the armies which fought under Abercromby, Moore, and Wellington were disciplined. When war broke out with France in 1793, Dundas was sent to Jersey to report on the practicability of a descent on St. Malo, after which he paid a short visit to the Duke of York's army before Dunkirk, where he served for a short time in command of a brigade, and then in October travelled through Germany and Italy to Toulon, where he took up the post of second in command to General O'Hara. When O'Hara was taken prisoner, Dundas took command of the small English force at Toulon; but he soon saw the impossibility of holding that city against the great superiority of the French troops. After repelling the attacks of 17 and 18 Dec. he became one of the chief advocates for the evacuation of that city, which was carried into effect on 29 Dec. He took his army to Elba and then to Corsica, where he superintended the capture of San Fiorenze, and then hurried across the continent to join the Duke of York in Flanders. He commanded a brigade of cavalry at the battle of Tournay on 22 May 1794, and when the Duke of York returned to England he received the command of the troops on the lower Waal, amounting to eight thousand men. With this force he fought the battle of Geldermalsen, and on 30 Dec. the battle of Tuyl, when, in spite of his inferiority of numbers, he drove the French back across the Waal. But it was impossible to hold the Waal for long, and Dundas had, in spite of his victories, to cover the disastrous retreat of the British army on Bremen with his cavalry. When Lord Harcourt returned to England with the infantry in April 1795, Dundas was left in command of twenty-four squadrons of cavalry, with which he served in Westphalia until the final recall of the troops from the continent in January 1796. He was largely rewarded for his great services, being appointed colonel of the 7th light dragoons on 23 Dec. 1795, made quartermaster-general at the Horse Guards in 1796, and promoted lieutenant-general and made governor of Landguard fort in 1797. As quartermaster-general he had much to do in reorganising the army after the disasters in Flanders, and in enforcing his 'Rules and Regulations.' He also commanded the camps of exercise at Weymouth and Windsor, which brought him into intimate relations with the king. In 1799 he accompanied the Duke of York in the expedition to the Helder. He commanded the second column in the battle of 19 Sept., and the centre column in the fierce attack on Bergen on 2 Oct., when his services were particularly praised by the Duke of York, but he felt obliged on the 17th to acquiesce in the convention of Alkmaer,as no good had been done and no ground gained by these battles. In 1801 he was made colonel of the 2nd dragoons and governor of Fort George in the place of Sir Ralph Abercromby, in 1802 he was promoted general, and in 1803 he resigned his post at the Horse Guards to take command of the southern district. In 1804 he was made a knight of the Bath and appointed governor of Chelsea Hospital, and in 1805 he resigned his command and retired to Chelsea, where he lived for the rest of his life. He acted as president of the court of inquiry held upon the conduct of Sir Hew Dalrymple, Sir Harry Burrard, and Sir Arthur Wellesley as to the convention of Cintra in 1808, and in the following year he was selected to succeed the Duke of York as commander-in-chief of the army. It was felt necessary that the duke should resign after the disclosures caused by the inquiry of the House of Commons into the case of Mrs. Mary Anne Clarke [q. v.], and it was considered best to choose some one who would at once carry out the great reforms begun by the duke, and be ready to resign to the duke when the scandal should have blown over. Dundas was chosen, because as the duke's right-hand man at the Horse Guards he thoroughly understood his military policy, besides being a most intimate friend. Dundas was accordingly sworn of the privy council, and held the post of commander-in-chief of the army from 18 March 1809 to 26 May 1811, a period signalised by the victories of Talavera and Busaco and the retreat to Torres Vedras, and he was then perfectly ready to resign to the Duke of York. He was transferred to the colonelcy of the 1st or king's dragoon guards in 1813, and lived quietly at Chelsea Hospital until his death there, at the age of eighty-five, on 18 Feb. 1820. Dundas, who married Charlotte, daughter of General Oliver de Lancey, barrackmaster-general, left no children. His widow died in April 1840, and his property devolved on his nephew, Robert Dundas of Beechwood in Midlothian, one of the principal clerks of the court of session in Scotland, who was created a baronet in 1821, and died 28 Dec. 1835.

Sir Henry Bunbury devotes the following passage to Sir David: 'General Dundas had raised himself into notice by having formed a system for the British army, compiled and digested from the Prussian code of tactics both for the infantry and the cavalry. This work had been eagerly adopted by the Duke of York, as commander-in-chief, and had become the universal manual in our service. The system was in the main good, and written on right principles, though the book was ill-written, and led the large class of stupid officers into strange blunders. But a uniform system had been grievously needed, for no two regiments, before these regulations were promulgated, moved in unison. Dundas was a tall, spareman, crabbed and austere, dry in his looks and demeanour. He had made his way from a poor condition (he told me himself that he walked from Edinburgh to London to enter himself as a fireworker in the artillery); and there were peculiarities in his habits and style which excited some ridicule among young officers. 'But though it appeared a little out of fashion, there was "much care and valour in that Scotchman"' (Narratives of some Passages in the Great War with France, 1799-1810).

[Royal Military Calendar, ed. 1820, i. 284-301; Chambers's Dict. of Eminent Scotsmen; Georgian Biography; Moore's Life of Sir John Moore; Bunbury's Narrative of some Passages in the Great War with France; Gent. Mag. March 1820.]